A dubious, suspicious, or potentially immoral or illegal past history. Investigators have begun looking into the shady past of the bankrupt company's CEO.I don't know, John, I wouldn't go out with a guy who has a shady past like that.
slang Older than; more than. I'm much more concerned about my health now that I'm on the shady side of 60.You're on the shady side of 20, which means you need to start acting more responsibly.
Fig. an untrustworthy person; a person who makes people suspicious. There is a suspicious character lurking about in the hallway. Please call the police.